Contact clip for circuit testing



Fb.6,1968 W.J.FAUL Em 3,368,187

CONTACT CLIP FOR CIRCUIT TESTING Filed May 21, 1965 Fl G. I I4 INVENTOR.WALTER J. FAUL BY REX L.EVATT ATTORNEYS" United States Patent 3,368,187CONTACT CLIP FOR CIRCUIT TESTING Walter J. Faul, 827 Pear, Sunnyvale,Calif. 94087, and Rex L. Evatt, 3571 Shafer, Santa Clara, Calif. 95051Filed May 21, 1965, Ser. No. 457,654 1 Claim. (Cl. 333-461) ABSTRACT OFTHE DISCLOSURE An elongated test clip for reaching deeply intoelectrical or electronic wired circuits is made by bending a singlelength of springy, electrically conductive wire so that a long, narrowloop of the wire has a single length of the wire disposed between thetwo sides of the loop and the free end of this single length formed intoa hook which extends beyond, and engages the transverse end portion ofthe loop to grip a conductor wire therebetween when the clip is in itsnormal condition. A hump is provided on the single length of wire at apoint remote from the hook end thereof, and projects upwardly beyond theloop, so that when the end of the clip thereon is inserted into wiredcircuitry, the hook may be separated from the transverse end of the loopby pressing the hump and the loop toward each other, thereby opening theclip to either grip or release a wire deep within the wired circuit.Insulating means are provided to cover the wires except at theirgripping ends, and means are provided for connecting a test conductor tothe other end of the clip.

The present invention relates to a contact clip, and pertains moreparticularly to a simple, inexpensive contact clip for electrical andelectronic circuit test use.

In working with various electrical and electronic circuits such as thosefound in radios, television sets and others, a common-implement employedis a spring clip having elongated, narrow electrically conductive jaws,frequently provided with teeth, and with spring means for urging thejaws toward closed condition. A well known type of such clip is known asan alligator clip. While useful for their intended purpose, many suchclips have the jaws and also the handle portions thereof of greaterwidth than is sometimes convenient for insertion into a position whereit is desired to use them. Also, it is sometimes difiicult to insulatesuch clips and still permit them to be manipulated.

An object of the present invention is to provide a simple, inexpensive,contact clip for electrical and electronic circuit test purposes.

Another object of the invention is to provide an electrical contact clipmade of a single length of electrically conductive spring wire, foldedupon itself, and bent in such a manner as to provide two jawsinteracting in such a manner as to permit the clip to be fastened ontoan electrical conductor.

Another object of the invention is to provide a electrical circuit testclip made of electrically conductive wire formed into two jaws, one jawconsisting of a length of wire with a terminal end portion bent upwardlytoward a transversely extending portion formed at the end of a secondjaw, the jaws being resiliently biased toward each other for gripping aconductor therebetween.

Another object is to make such a clip wherein one of the jaws has a humptherein intermediately of its length, so that when the humped portion ofone jaw is squeezed toward the other jaw the tips of the jaws will beseparated to receive a conductor therebetween.

The foregoing objects and advantages of the invention will be apparentfrom the following description and the accompanying drawings, wherein:

3,368,187 Patented Feb. 6, 1968 FIG. 1 is a top plan view of a springclip embodying the invention, and with the connector sleeve removedendwise therefrom.

FIG. 2 is a side elevational view of the clip shown in FIG. 1 as itappears when secured by its connector sleeve to a conductor wire, thebroken lines showing the clip opened by squeezing it between the thumband forefinger of the users hand.

FIG. 3 is a perspective view of the clip shown in FIGS. 1 and 2 as itappears when gripping a conductor wire.

FIG. 4 is a view similar to FIG. 3 but without the conductor wire, andshowing a length of plastic insulation sleeve material fitted thereon.

FIG. 5 is a perspective view of a modified form of the invention.

Brief description Briefly, the illustrated form of the inventioncomprises a spring contact clip A preferably made from a single lengthof wire, and comprising an elongated loop 10 forming one jaw of the cliand a wire portion 11 extending between the two sides of the loop 10,and forming the other jaw of the clip, the intermediate wire portion 11terminating at its free end in an upwardly bent, hooked end portion 12.The intermediate wire portion 11 has a hump formed therein so that itcan be opened as shown in dotted lines in FIG. 2 to receive a conductor13 (FIG. 3) in gripped relation between its jaws.

Detailed description In the form of the invention shown in FIGS. 1-4 theclip A is made from a single length of wire of suitable conductivematerial, such as, for example, spring bronze. This length of wire isbent sharply, reversely upon itself, at a point 14 approximatingone-third of its length. The two-thirds portion of its length on Oneside of this reverse bend 14 is bent reversely upon itself to form theloop 10, having a curved end portion 15 and parallel, straight sideportions 17 and 18. The straight side portions 17 and 18 are spacedapart a suitable distance, for example approximately six times thediameter of the wire employed, although this spacing is optional. Thetwo side portions 17 and 18 of the loop are bent angularly inwardlytoward each other at 19 and 20, respectively, and, then extend parallel,and in close, abutting, sideby-side relation with the base portion ofthe intermediate wire portion 11 to provide a plug portion 21 forinsertion into a tubular connector sleeve 2-2 of electrically conductivematerial. The end portion of the tubular connector sleeve 22 into whichthe plug portion 21 is inserted is then flattened upon the plug portion21 as shown in FIGS. 2 and 3 to lock the plug portion firmly within theconnector sleeve.

The remaining approximately one-third portion of the length of the wirewhich forms the clip A comprises the intermediate wire portion 11. Thelatter is bent initially slightly upwardly at the end of the plugportion 21, and then downwardly to form the hump 23. From the hump 23the wire portion 11 extends angularly downwardly to pass beneath thecurved end portion 15 of the loop 10, where it is again bent upwardly toform the hooked end 12, which extends just beyond the curved end portion15 of the loop 10. The intermediate wire portion 11 is biased, as bybending, so that the hooked end portion 12 tends to resiliently grip aconductor wire 24 or other work piece positioned between the two jawsformed by the loop 10 and the intermediate wire portion 11.

To connect the clip A to a conductor, such as an insulated wire 24 (FIG.2) an end portion 24a of the conductor wire is stripped of itsinsulation and is inserted in the opposite end of the connector sleeve22 from that which grips the plug portion 21. The opposite end portionof the connector sleeve 22 is then flattened to grip the conductor wire24 as shown in FIGS. 2 and 3.

The Operation of the clip A is best illustrated in FIGS. 2 and 3. Toopen the clip the latter is seized between the thumb 2'7 and a finger 28of a users hand, with one thereof positioned on the hump 23, and theother beneath the loop 10. The thumb and finger are then squeezedtogether, as shown in broken lines in FIG. 2, thereby Opening the jawsto their dotted line position of FIG. 2. Release of the pressure permitsthe spring bias of the clip to urge it toward its closed position ofFIGS. 1, 3 and 4.

In FIG. 4 the clip is shown enclosed in an insulative sleeve B of wellknown, thin, plastic sleeving of a type commonly employed for similarpurposes by electricians. This insulative sleeve B increases the size ofthe clip very little, and permits it to be used in its normal mannershown in FIG. 2. The insulative sleeve can be slidably moved as close tothe gripping end of the clip as desired, or even over the griping end ofthe clip while the latter is being inserted through wires in a circuit,which wires otherwise might be accidentally shorted if touched by theconductive material of the clip itself. The narrow structure of thepresent clip permits the use of a small sleeve for this purpose which isnot true of clips having the usual widely separated gripping handles.

in the modified form of the invention shown in FIG. 5 the clip A isgenerally similar to that shown in FIGS. l4, the only difference beingthat one side of the loop from a point just beyond the curved endportion thereof is omitted. Otherwise the clip A is similar to, andoperates in the same manner as the clip A shown in FIGS. 14. Thismodified structure shown in FIG. 5 results in a substantial saving inthe amount of wire required for making the clip, and for many uses isquite satisfactory. The various parts of FIG. 5 are designated by thesame reference numerals as corresponding parts of FIGS. 1-4 with theprime added thereto.

The invention provides a simple, extremely inexpensive, narrow andeiTective contact clip for electrical test use. It also provides a clipwhich is well adapted to high speed, automatic production.

While we have illustrated and described a preferred embodiment of thepresent invention and one modified form thereof, it will be understood,however, that various changes and modifications may be made in thedetails thereof without departing from the scope of the invention as setforth in the appended claims.

Having thus described the invention, what we claim as new and desire toprotect by Letters Patent is defined in the following claim:

1. A contact clip for probing deeply into a wired electrical circuit forgripping and electrically contacting a selected conductor wire of thecircuit comprising:

a length of springy, electrically conductive wire,

a sharp reverse bend formed in the length of wire at a pointintermediate its ends,

a rounded reverse bend formed substantialy medially in the portion ofthe length of wire on one side of the sharp bend to form thereof anelongated, narrow loop,

the portion of the length of wire on the other side of the sharp reversebend therein extending substantially medially lengthwise of the loop,and extending slightly beyond the reversely bent portion of the lengthof wire forming the loop,

a hook formed on the end portion of the medially extending portion ofthe length of wire remote from the sharp reverse bend,

the portions of the length of wire on opposite sides of the sharpreverse bend being formed to bias the hook formed on the mediallyextending portion of the length of wire toward the rounded reverse bendin the portion of the length of wire forming loop, a hump formed in themedially extending portion of wire remote from the hook end thereof,said hump projecting through, and laterally beyond the loop, so thatwhen pressure is exerted by griping the hump and urging it toward theloop it will separate the hook from the end of the loop, and insulatingmeans covering the loop and the medially extending wire portion with theexception of the hook and the rounded reverse bend in the loop, both ofwhich are bare for electrical contact with a circuit wire grippedtherebetween.

References (liter! UNITED STATES PATENTS 542,803 7/1895 Palmer 24-131 X582,788 5/ 1897 Huebener.

700,208 5/1902 Lafo et a1. 24-261 1,938,261 12/1933 Richardson 339-2612,627,095 2/1953 Ralmieri 24-261 X 3,123,427 3/1964 Yopp 339-2623,188,605 6/ 1965 Slenker.

FOREIGN PATENTS 1,232,430 4/ 1960 France.

312,343 5/1919 Germany. 160,375 3/1920 Great Britain.

MARVIN A. CHAMPION, Primary Examiner.

PERRY TEITELBAUM, Assistant Examiner.

